Alloy G

HuaNickel AlloyG is a Ni-Fe-Cr-Mo-Cu-Nb deformed corrosion-resistant alloy developed in the mid-60s of the 20th century, which is resistant to both H₂SO₄ corrosion and H₃PO₄ corrosion. In addition to its good corrosion resistance in H₂SO₄ and H₃PO₄, the alloy also has excellent corrosion resistance in redox media. In mixed media containing fluorosilicic acid, sulfate, chloride, fluoride, nitrate H₂SO₄ and H₃PO₄. The alloy also has good resistance to localized corrosion, such as intergranular corrosion, pitting corrosion, and crevice corrosion.

AlloyGChemical composition：

	Ni	Cr	Mo	Nb	Fe	Cu	Si	Mn	S	Co	W	C
Min	Bal	21	5.5	1.75	18	1.5	≤
Max		23.5	7.5	2.5	21	2	1	1	0.03	2.5	1	0.05

AlloyGPhysical properties：

Temperature/℃	22
Densityp/g·cm-3	8.31
Temperature/℃	21～9321～20421～31621～42621～53821～649
Coefficient of linear expansion/×10-6·℃-1	13.4  13.8  14.3  14.9  15.7  16.4
Temperature/℃	25  100  200  300  400  500  600  700  800  900
Thermal conductivityλ/W·(m·℃)-1	10.1  11.2  12.8  14.3  15.9  17.5  19.2  20.8  22.4 24.0
Temperature/℃	0  100  200  300  400  500  600  700  800  900  1000
Specific heat capacityc/J·(kg·℃)-1	388  455  481  501  518  535  552  568  585  602 619

AlloyGMechanical properties：

Type of material	temperature/℃	db/MPa	oo.2/MPa	δs/%	ψ/%
<3.0mmboard	-160 -65 room temperature 93 204 315 426 538 649 760	834 783 700 665 624 604 584 562 523 440	443 400 317 289 256 245 229 225 220 216	48 50 61 56 74 82 84 83 82 61	52 52 50 47 48 47 47 46 41
13mmboard Transverse welding	room temperature 260 538	694 600 538	415 341 273	32 43 43	23 53 54
Welding metals	room temperature 260 538	746 596 542	518 409 379	23 28 27	31 36 38

AlloyGAlloy properties：

Under certain heating conditions, such as sensitization in the range of 650~1093°C, the alloy will precipitate M₆C, MC carbides, Laves phase (Fe₂Mo) and intermetallic Z phase (Cr-Fe-Ni-Nb). The precipitation of aging precipitation at medium temperature will have a very negative effect on the corrosion resistance of the alloy, especially the resistance to intergranular corrosion.

AlloyGUses of alloys：

This alloy is used in the manufacture of sulfuric acid, phosphoric acid, wet phosphoric acid, dissolved fluids for nuclear fuels, dissolved fluids for pollution control and the paper industry, as well as pipes, vessels, heat exchangers, pumps, and valves in the production of oil and gas wells.

AlloyGProcess performance：

Welding process: HuaNickel AlloyG has good welding performance, can be welded by conventional welding methods, no heat treatment is required before and after welding. The heat input should be controlled during welding, and the interlayer temperature should be ≤150°C. The solder core material is Nicrofer S6020, and its composition is 0.05C-21Cr-9Mo-3Nb-65Ni.

Heat treatment: In order to obtain the best corrosion resistance of the alloy, the solution annealing temperature should be 1100~1150 °C, the holding time depends on the cross-sectional size of the product, and the cooling method is water cooling or rapid air cooling.

Relevant standards：

ASTM B581 、ASTM B582 、 ASTM B619 、ASTM B622 、ASTM B626